Assembled mud-rock flow debris dam and construction method thereof

ABSTRACT

A rapidly assembled debris flow sediment storage dam and a construction method are provided. The sediment storage dam has a main dam body with multiple prefabricated reinforced concrete rectangular boxes linked by vertical and horizontal connections. The top surface of each rectangular box is open, and the other five surfaces of the rectangular box are closed. Soil is used to fill each rectangular box. The main dam body is assembled above dam body foundations. Dam abutment foundations of the sediment storage dam and the inside slope of the dam body are filled with cement-laid stone masonry or concrete, while the top surface of the dam crest is also sealed using cement-laid stone masonry or concrete.

BACKGROUND

This invention relates to a debris flow prevention and control technology, and more particularly, to a rapidly assembled dam body-based, debris flow sediment storage dam formed of rectangular boxes and a construction method thereof.

Debris flow disasters are major geological disasters in China and other countries. As the economy in mountainous areas and the western regions develops, there is an urgent need for debris flow management. As a major form of debris flow prevention and control, sediment storage dams have been used extensively in debris flow prevention and control projects.

Traditionally, sediment storage dams generally comprise cement and laid stone masonry structures, concrete structures, or reinforced concrete structures. The construction method used for the specific sediment storage dam is determined by the areas where the construction occurs. The current structures and construction methods used for sediment storage dams have the following deficiencies. First, due to foundation excavation, material piling, concrete mixing and other conditions, severe environmental disruption of the construction site readily occurs. Secondly, construction periods are often prolonged, because the construction of sediment storage dams is highly dependent on seasons; thus, the construction is generally implemented in the dry season, which means that the working procedures must be planned carefully, otherwise, the whole project will be affected if a single link is delayed. Thirdly, the construction is highly dependent on local materials, which are generally soil bodies with an extremely high viscous material content, so low in gravel content and soil strength that cannot be used as the cement-laid stone masonry and concrete materials; therefore, the stone used for the cement-laid stone masonry and the aggregates mixed with concrete in the ditches need to be transported from the outside, which increases the cost significantly.

SUMMARY

One purpose of the present invention is to produce a rapidly assembled debris flow sediment storage dam, to overcome the known deficiencies during the construction of existing sediment storage dam types wherein the on-site environmental damage is significant, the transportation of construction materials is difficult, the construction period is long, and the construction is constrained greatly by the construction season. By contrast, the rapidly assembled debris flow sediment storage dam according to the present invention can be constructed readily, causes minor environmental damage, and fully utilizes the soil body materials present in any ditches.

The technical solution of the invention is as follows.

A rapidly assembled debris flow sediment storage dam is provided, which comprises a main dam body with numerous prefabricated reinforced concrete rectangular boxes that link together via vertical and horizontal connection (i.e., each rectangular box is connected with other rectangular boxes at the front and back of the rectangular box, on the left and right of the rectangular box, and above and below the rectangular box). The top surface of each rectangular box is open and the other five surfaces of the rectangular box are closed. Each rectangular box is filled with soil and the main dam body is arranged on the dam body foundations, wherein the dam abutment foundations of the debris flow sediment storage dam and the inside slope of the dam body are filled with cement-laid stone masonry or concrete, while the top surface of the dam crest is sealed using cement-laid stone masonry or concrete. The rectangular boxes that constitute the main dam body are prefabricated, which reduces both the overall construction period and the effects of the sediment storage dam on the surrounding environment. The top surface of each rectangular box is open and the other five surfaces of the rectangular box are closed, which facilitates the vertical and horizontal connection of the rectangular boxes and filling the rectangular boxes with soil. A sediment storage dam assembled from rectangular boxes with the structure described above can withstand bidirectional forces acting in the horizontal and vertical directions simultaneously, so the sediment storage dam has high compressive strength and stability, which means that it can effectively resist the impact of debris flows.

The geometric proportions of the rectangular boxes are determined by the size of the sediment storage dam, while the volume of the sediment storage dam is planned based on the actual conditions in the debris flow area. The geometric proportions of the rectangular boxes are calculated based on the following principles. (i) The net dam height H between the overflow portion of the dam body and the dam body foundation is an integral multiple of the height h of each rectangular box, i.e., h=H/n1, where n1 is a multiple. (ii) The length b of the short edge of each rectangular box is determined by the width B of the dam crest or the gradient 1:m of the inside slope of the dam body, where the length b of the short edge of the rectangular box is determined according to the width B of the dam crest, while the width B of the dam crest is an integral multiple of the length b of the short edge of the rectangular box, i.e., b=B/n2, where n2 is a multiple. The length b of the short edge of the rectangular box is determined according to the gradient 1:m of the inside slope of the dam body, so the gradient 1:m of the inside slope of the dam body is twice the ratio of the height h of the rectangular box to the length b of the short edge of the rectangular box, i.e., 2h/b=1:m, which means that b=2mh. (iii) To maximize the filling of the dam body space using the rectangular boxes, the rectangular boxes can be arranged in a crisscross pattern in the plane, which enhances the plane stability. Therefore, the length a of the long edge of the rectangular box can be three sizes, i.e., the length a of the long edge of the rectangular box (1) is equal to the length b of the short edge of the rectangular box (1), or twice the length of the length b of the short edge of the rectangular box (1), or three times the length of the length b of the short edge of the rectangular box (1).

Given the compressive strength limitation of each rectangular box in the vertical direction, the net dam height H between the overflow portion of the dam body of the rapidly assembled debris flow sediment storage dam made of rectangular boxes and the dam body foundation is less than or equal to 10.0 m. The height h of each rectangular box is generally 0.5-1.0 m, which ensures the stability of the rectangular box. To facilitate the hoisting of a single box, the weight of the rectangular box is kept below 2000 kg as far as possible, i.e., the weight of the rectangular box is less than or equal to 2000 kg. To further facilitate hoisting, hoisting hooks can be positioned on the inside walls at two ends of each rectangular box.

The prefabricated rectangular boxes are open and thin-walled uncapped cuboids, where the length a of the long edge of each rectangular box is twice the length b of the short edge of the rectangular box. There is one transverse partition parallel to the short edge of the rectangular box in the rectangular box and, if the length a of the long edge of the rectangular box is three times the length b of the short edge of the rectangular box; there are two transverse partitions parallel to the short edge of the rectangular box in the rectangular box. These transverse partitions are added to increase the strength of the rectangular boxes. The thickness t₁ of the side wall of each rectangular box is designed, so that the rectangular box can withstand the pressure of the rectangular boxes above the rectangular box and the impact force of the debris flow. In general, this thickness is 0.08-0.12 m, while the thickness t₂ of the baseplate of each rectangular box and that of each transverse partition is 0.06 m.

The rectangular boxes are reinforced concrete structures and the side walls of each rectangular box include single-sided or double-sided reinforcement. The baseplate of each rectangular box and each transverse partition have single-sided reinforcement. The overall reinforcement ratio per unit volume is 0.5-2.0%, the diameter of each steel bar is 0.006-0.012 m, and the concrete used is generally C35, C30, or C25.

In general, the heights of the rectangular boxes that comprise the main dam body are equal on the same layer, which ensures the surface integrity of the rectangular boxes on the same layer. During the prefabrication process, the side wall of each rectangular box is provided with horizontal connecting holes to facilitate the transverse connection of the rectangular boxes and with horizontal connecting holes, which can be connected using bolts. There are 2-4 horizontal connecting holes in the side wall of the short edge of each rectangular box while the number of horizontal connecting holes in the side wall of the long edge of each rectangular box is a multiple, i.e., 2-12. The positions of the horizontal connecting holes facilitate the anterior-posterior and left-right connections of the rectangular boxes, wherein the diameter of each horizontal connecting hole is generally 0.02-0.03 m. During the prefabrication process, the baseplate of each rectangular box and the side wall of each rectangular box are provided with drainage holes, which allows the complete draining of water from the rectangular boxes. This reduces the pressure caused by the weight of water in the rectangular boxes and reduces the horizontal thrust of the debris flow into the dam body caused by the draining water in the debris flow body in the reservoir of the dam body. There are 2-4 drainage holes on the side wall of the short edge of each rectangular box and the number of drainage holes on the side wall of the long edge of each rectangular box is a multiple, i.e., 2-12. There are also 2-4 drainage holes in the baseplate. The drainage holes are round and typically 0.03-0.06 m in diameter. During the prefabrication process, to increase the connections between the upper and lower layers of rectangular boxes, the four corners of the baseplate of each rectangular box have vertical connecting holes, which facilitate the longitudinal connection of rectangular boxes (if transverse partitions are present in a rectangular box, the rectangular box is separated into two or three small boxes and four corners of each separate box have vertical connecting holes). The connections are made by passing a steel bar through the vertical connecting holes, which is welded to steel bars extending from the side walls of the rectangular boxes in the upper and lower layers. Each vertical connecting hole measures 0.03×0.03-0.04×0.04 m².

The rectangular boxes are filled with soil, which is obtained from ditches as much as possible. The maximum grain size of the soil body used to fill each rectangular box is determined by the length b of the short edge of the rectangular box, which is generally half of the length b of the short edge of the rectangular box (i.e., b/2). Thus, the rectangular boxes are filled after soil grains larger than the maximum grain size have been removed by sieving. To ensure the strength of the dam body, the filled soil bodies are tamped and vibrated intensely. The method used to construct the rapidly assembled debris flow sediment storage dam comprises the following specific steps.

A. Planning and designing the space sizes (including the net dam height H between the overflow portion of the dam body and the dam body foundation, the width of the dam crest, and the gradient 1:m of the inside slope of the dam body) of the sediment storage dam based on the actual situation in the debris flow area. Planning the geometric proportions (including the height h of each rectangular box, the length b of the short edge of each rectangular box, and the length a of the long edge of each rectangular box) of each prefabricated rectangular box based on the size of the sediment storage dam. Planning the space-filled position of each prefabricated rectangular box in the sediment storage dam based on a façade, i.e., planning the position and the aspect of each rectangular box in the sediment storage dam.

B. Excavating the foundations of the sediment storage dam based on the designed excavation lines of the foundations. Treating the bottom of the foundations using reinforced concrete, or concrete with cement-laid stone masonry, to produce the dam body foundations. Preparing the rectangular boxes at sites away from the sediment storage dam.

C. Hoisting the prefabricated reinforced concrete rectangular boxes layer upon layer from the bottom to the top, beginning with the dam body foundation. Implementing the vertical and horizontal connections of the rectangular boxes (i.e., each rectangular box is connected with the rectangular boxes at the front and back of the rectangular box, on the left and right of the rectangular box, and above and below the rectangular box). After the rectangular boxes have been hoisted into each layer, the rectangular boxes are filled with soil excavated from the ditches produced by excavating the foundations. The soil is tamped and vibrated intensely to form the dam body.

D. Filling the dam abutment foundation of the sediment storage dam with cement-laid stone masonry or concrete (i.e., any gap between a rectangular box and the foundation that cannot be filled with a rectangular box are filled with cement-laid stone masonry or concrete, which completes the dam abutment foundation). Filling the inside slope (i.e., a part that cannot be filled with the rectangular boxes) of the dam body of the sediment storage dam with cement-laid stone masonry or concrete to complete the designed dam body pattern.

E. Sealing the top surface of the dam crest using cement-laid stone masonry or concrete to complete the rapidly assembled debris flow sediment storage dam.

Compared with the current method, the rapidly assembled debris flow sediment storage dam and its construction method, which are disclosed in this invention description, have many benefits. In particular, the rectangular boxes can be assembled rapidly while the preparation of the rectangular boxes and the construction of the dam body foundation of the sediment storage dam can be performed simultaneously, which reduces the construction period greatly. The rectangular boxes can be prepared at sites away from the sediment storage dam, which reduces the effects of the construction of the sediment storage dam on the surrounding environment. The effects of building materials leaking into ditches are eliminated because the soil dug from the construction ditches is used to fill the rectangular boxes, which overcomes the problem of transporting massive amounts of construction materials. Compared with traditional sediment storage dams, the construction costs of the sediment storage dam system disclosed in this invention can be reduced by 20-50%, while the construction period can be reduced by 20-80%.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and benefits of the present invention will be made apparent with reference to the following specification and accompanying drawings, where like reference numerals refer to like features across the several views, and wherein:

FIG. 1 is a diagrammatic sketch of the rectangular box wherein the length a of the long edge of the rectangular box is equal to the length b of the short edge of the rectangular box;

FIG. 2 is a diagrammatic sketch of the rectangular box wherein the length a of the long edge of the rectangular box is twice the length b of the short edge of the rectangular box;

FIG. 3 is a diagrammatic sketch of the rectangular box wherein the length a of the long edge of the rectangular box is three times the length b of the short edge of the rectangular box;

FIG. 4 is a diagram showing the structure of the rapidly assembled debris flow sediment storage dam; and

FIG. 5 is a left view of the rapidly assembled debris flow sediment storage dam.

The numbered labels in the figures indicate the following.

1 rectangular box 2 dam foundations 3 inside slope 4 dam crest 5 transverse partition 6 horizontal connecting holes 7 drainage hole 8 vertical connecting hole 9 dam abutment foundations a: the length of the long edge of b: the length of the short edge of each each rectangular box rectangular box h: the height of each H: the net dam height between rectangular box the overflow portion and the dam body foundation B: the width of the dam crest 1: m: the gradient of the inside slope of the dam body t₁: the thickness of the side wall t₂: the thickness of the transverse of each rectangular box partition

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

By reference to the accompanying figures, embodiments of the invention are described further as follows.

Embodiment 1

As shown in FIGS. 1, 2, 3, 4, and 5, the area of the drainage basin of the debris flow gully is 5.6 km². To control debris flow disasters, five check dams, one sediment storage dam, and a 700 m drain/guide groove are placed in the middle of the drainage basin. The sediment storage dam is implemented using the following construction method.

Step 1: Depending on the situation of the drainage basin of the debris flow gully, the net dam height H between the overflow portion of the sediment storage dam and the dam body foundation (2) is set at 6.0 m, the width B of the dam crest (4) is 2.0 m, and the gradient 1:m of the inside slope of the dam body is 1:0.67. The net dam height H of the dam is less than or equal to 10.0 m, so the assembled debris flow sediment storage dam described by the invention needs to be planned for this level. The rapidly assembled debris flow sediment storage dam comprises a main dam body with many prefabricated reinforced concrete rectangular boxes (1), which have vertical and horizontal connection. The top surface of each rectangular box (1) is open whereas the other five surfaces of each rectangular box (1) are closed. The geometric proportions of each prefabricated rectangular box (1) are planned according to the size of the sediment storage dam, as follows: (i) based on a situation where the net dam height H between the overflow portion of the dam body and the dam body foundation (2) is an integral multiple n1 of the height h of each rectangular box, n1 is set to 12 initially, so the height h of the rectangular box (1) is equal to 0. 5 (6.0/12) m; (ii) based on a situation where the width B of the dam crest (4) is an integral multiple n2 of the length b of the short edge of the rectangular box, n2 is set to 2 initially, so the length b of the short edge of the rectangular box (1) is equal to 1.0 (2.0/2) m; and (iii) the length a of the long edge of the rectangular box (1) can be set to three sizes, i.e., the length a of the long edge of the rectangular box (1) is set to 1.0 m, 2.0 m, or 3.0 m (shown in FIGS. 1, 2, and 3, respectively).

The space-filling positions of the three types of prefabricated rectangular boxes (1) in each sediment storage dam layer are planned based on the design of the façade of the sediment storage dam, as shown in FIGS. 4 and 5.

Step 2: The foundations of the sediment storage dam are excavated according to the design of the excavation line for the foundations of the planned sediment storage dam, and the bottom of the foundations are treated using concrete C20 to form the dam body foundations. During the excavation and treatment of the foundations, the three types of rectangular boxes planned in step 1 are prepared at sites away from the sediment storage dam.

During the prefabrication process, a transverse partition (5) is added parallel to the short edge of the rectangular box (1) (the length a of the long edge is equal to 2.0 m), while two transverse partitions (5) are added parallel to the short edge of the rectangular box (1) (the length a of the long edge is equal to 3.0 m). The thickness t_(i) of the side wall of each rectangular box (1) is 0.08 m, while the thickness t₂ of the baseplate of each rectangular box (1) and each transverse partition (5) is 0.06 m. The three sizes of rectangular boxes are all reinforced concrete structures and the side wall, baseplate, and transverse partition (5) of each rectangular box (1) possess single-sided reinforcements. The overall reinforcement ratio per unit volume is 0.5%, the diameter of each steel bar is 0.006 m, and the concrete used is C30. The weights of the three types of rectangular boxes (1) never exceed 2000 kg, which facilitates the transportation of the rectangular boxes on a tractor road in a ditch using a small tractor, while it also facilitates the hoisting of the rectangular boxes using simple manual equipment.

During the prefabrication process, the side wall of each rectangular box (1) is provided with horizontal connecting holes (6) to facilitate transverse connections between rectangular boxes (1) using bolts. There are two horizontal connecting holes (6) on the side wall of the short edge of each rectangular box (1). There are two, four, and six horizontal connecting holes (6) in the side walls of the long edges of the three different sizes of rectangular boxes (1). The diameter of each horizontal connecting hole (6) is 0.02 m. The baseplate of each rectangular box (1) and the side wall of each rectangular box are provided with drainage holes (7), there are two drainage holes (7) in the side wall of the short edge of each rectangular box (1) and two in the baseplate of each rectangular box. There are two, four, and six drainage holes (7) in the side walls of the long edges of the three sizes of rectangular boxes (1). The drainage holes (7) are round holes with a diameter of 0.03 m. The four corners of the baseplate of each rectangular box (1) each have a vertical connecting hole (8) to facilitate the longitudinal connection of the rectangular boxes (1) (for a rectangular box with transverse partitions inside, the rectangular box is separated into two or three small boxes and the four corners of each separate box have vertical connecting holes (8)). The connections are implemented by passing a steel bar through the vertical connecting holes (8), which is welded to steel bars extending from the side walls of the rectangular boxes in the upper and lower layers. Each vertical connecting hole (8) measures 0.03×0.03 m².

Step 3: The reinforced concrete rectangular boxes (1) prefabricated in step 2 are hoisted layer upon layer from the bottom to the top, beginning with the dam body foundations (2). The rectangular boxes (1) are then linked vertically and horizontally by their horizontal connecting holes (6) and vertical connecting holes (8). After the rectangular boxes (1) have been hoisted onto each layer, the soil excavated from ditches when constructing the foundations is used to fill the rectangular boxes (1). The soil is tamped and vibrated intensely to form the dam body. The maximum grain size of the soil used to fill the rectangular boxes (1) is 0.5 m.

Step 4: The dam abutment foundations (9) of the sediment storage dam are filled with concrete type C20, while the inside slope of the dam body of the sediment storage dam is also filled with concrete type C20 to form the designed dam body pattern.

Step 5: The top surface of the dam crest (4) is sealed using concrete type C20 to complete the assembly of the debris flow sediment storage dam. The structure of the rapidly assembled debris flow sediment storage dam comprises the main dam body with many prefabricated reinforced concrete rectangular boxes (1), which are linked by vertical and horizontal connections. The top surface of each rectangular box (1) is open, whereas the other five surfaces of the rectangular box (1) are closed. Soil is used to fill each rectangular box (1) and the main dam body is arranged above the dam body foundations (2). The dam abutment foundations (9) of the rapidly assembled debris flow sediment storage dam and the inside slope (3) of the dam body are filled with concrete, while the top surface of the dam crest (4) is sealed with concrete.

Embodiment 2

As shown in FIGS. 1, 2, 4, and 5. The descriptions of the common steps in embodiments 1 and 2 are not repeated. The differences between embodiments 1 and 2 are as follows.

Step 1: Based on a situation where the area of the drainage basin of the debris flow gully is 10.0 km², the net dam height H between the overflow portion of the sediment storage dam and the dam body foundation (2) is set to 10.0 m, the width B of the dam crest (4) is 3.0 m, and the gradient 1:m of the inside slope of the dam body is 1:0.7. The net dam height H of the dam is less than or equal to 10.0 m, so the appropriate rapidly assembled debris flow sediment storage dam method, which is disclosed in the details of this invention, is used. The geometric proportions of each prefabricated rectangular box (1) are planned based on the size of the sediment storage dam, as follows: (i) based on the situation where the net dam height H between the overflow portion of the dam body and the dam body foundations (2) is an integral multiple n1 of the height h of the rectangular box, n1 is set to 10 initially, so the height h of the rectangular box (1) is equal to 1 (10.0/10) m; (ii) based on the situation where the gradient of the inside slope of the dam body is twice the ratio of the height h of the rectangular box relative to the length b of the short edge of the rectangular box, the length b of the short edge of the rectangular box (1) is equal to 1.4 m (2×1.0×0.7); and (iii) the length a of the long edge of the rectangular box (1) is set to different two sizes, i.e., the length a of the long edge of the rectangular box (1) is set to 1.4 m and 2.8 m (shown in FIGS. 1 and 2, respectively).

Step 2: The base of the foundations is treated using cement-laid stone masonry to form the dam body foundations. The thickness t_(i) of the side wall of each rectangular box (1) is 0.12 m. Both sizes of the rectangular boxes (1) are reinforced concrete structures, where the side wall of each rectangular box (1) has double-sided reinforcement, the baseplate of each rectangular box (1) and each transverse partition (5) have single-sided reinforcement, and the overall reinforcement ratio per unit volume is 2.0%. The diameter of each steel bar is 0.12 m and the concrete type is C35. Thus, the weights of the two types of rectangular boxes never exceed 2000 kg, which facilitates the transport of the rectangular boxes along a tractor road in a ditch using a small tractor, while it also facilitates the hoisting of the rectangular boxes using simple manual equipment. There are four horizontal connecting holes (6) in the side wall of the short edge of each rectangular box (1). There are four and eight horizontal connecting holes (6) in the side walls on the long edges of the two sizes of rectangular boxes (1). The diameter of each horizontal connecting hole (6) is 0.03 m. There are four drainage holes (7) in the side wall of the short edge of each rectangular box (1) and in the baseplate of each rectangular box (1). There are four and eight drainage holes (7) in the side walls on the long edges of the two sizes of rectangular boxes (1). The drainage holes (7) are round holes with a diameter of 0.06 m. The size of each vertical connecting hole (8) is 0.04×0.04 m².

Step 3: The maximum grain size of the soil used to fill the rectangular boxes (1) is 0.7 m.

Step 4: The dam abutment foundations (9) of the sediment storage dam are filled with cement-laid stone masonry and the inside slope (3) of the dam body of the sediment storage dam is filled with cement-laid stone masonry, which forms the designed dam body pattern.

Step 5: The top surface of the dam crest (4) is sealed using cement-laid stone masonry to complete the rapidly assembled debris flow sediment storage dam. The structure of the rapidly assembled debris flow sediment storage dam comprises the main dam body with many prefabricated reinforced concrete rectangular boxes (1), which are linked by vertical and horizontal connections. The top surface of each rectangular box (1) is open, whereas the other five surfaces of the rectangular box (1) are closed. Soil body is used to fill each rectangular box (1). The main dam body is assembled on the dam body foundations (2). The dam abutment foundations (9) of the rapidly assembled debris flow sediment storage dam and the inside slope (3) of the dam body are filled with cement-laid stone masonry, while the top surface of the dam crest (4) is also sealed using cement-laid stone masonry. 

1-10. (canceled)
 11. A rapidly assembled debris flow sediment storage dam, comprising: at least one dam body foundation; a main dam body provided on the dam body foundation, the main dam body comprising a plurality of prefabricated reinforced concrete rectangular boxes, the boxes being linked by vertical and horizontal connections, wherein the top surface of each box is open and the other five surfaces of each box are closed; soil for filling each box; at least one dam abutment foundation, wherein the at least one dam abutment foundation and an inside slope of the main dam body are filled with at least one of cement-laid stone masonry and concrete; and a dam crest, the top surface of which is sealed using at least one of cement-laid stone masonry and concrete.
 12. The assembled debris flow sediment storage dam according to claim 11, wherein: the net dam height between a overflow portion of the main dam body and the at least one dam body foundation is an integral multiple of the height h of each box; the width of the dam crest is an integral multiple of the length of the short edge of each box, or the gradient 1:m of the inside slope of the main dam body is twice the ratio of the height of each box relative to the length of the short edge of each box; and the length of the long edge of each box is equal to the length of the short edge of each box , or twice the length of the short edge of the each box, or three times the length of the short edge of each box.
 13. The assembled debris-flow sediment storage dam according to claim 12, wherein the net dam height between the overflow portion of the main dam body and the dam body foundation is less than or equal to 10.0 m, the height of the rectangular box is in the range of 0.5-1.0 m, and the weight of each box is less than or equal to 2000 kg.
 14. The assembled debris flow sediment storage dam according to claim 12, wherein: if the length of the long edge of each box is twice the length of the short edge of each box, a transverse partition is added parallel to the short edge in each box; if the length of the long edge of each box is three times the length of the short edge of each box, two transverse partitions are added parallel to the short edge of each box.
 15. The assembled debris flow sediment storage dam according to claim 14, wherein the thickness of the side wall of each box is 0.08-0.12 m, and the thickness of the baseplate of each box and each transverse partition is 0.06 m.
 16. The assembled debris flow sediment storage dam according to claim 14, wherein the side wall of each box comprises a single-sided reinforcement or a double-sided reinforcement, the baseplate of each box and the transverse partitions comprise a single-sided reinforcement, the overall reinforcement ratio per unit volume is 0.5-2.0%, and the single-sided reinforcement or the double-sided reinforcement comprises a plurality of steel bars each having a diameter of 0.006-0.012 m.
 17. The assembled debris flow sediment storage dam according to claim 11, wherein the side wall of each box have horizontal connecting holes to facilitate the transverse connection of the box, the baseplate and the side wall of each box have drainage holes, and the four corners of the baseplate of each box have a vertical connecting hole to facilitate the longitudinal connection of the box.
 18. The assembled debris flow sediment storage dam according to claim 17, wherein the numbers of horizontal connecting holes and drainage holes on the side wall of the short edge of each box are in the range of 2-4, the numbers of horizontal connecting holes and drainage holes on the side wall of the long edge of each box are in the range of 2-12, the diameter of each horizontal connecting hole is in the range of 0.02-0.03 m, and the diameter of each drainage hole is in the range of 0.03-0.06 m, and the size of each vertical connecting hole is 0.03×0.03-0.04×0.04 m².
 19. The assembled debris flow sediment storage dam according to claim 12, wherein the maximum grain size of the soil used to fill each box is half the length of the short edge of each box.
 20. A method for constructing an assembled debris flow sediment storage dam, the method comprising: determining the size of the sediment storage dam based on the environment; determining the geometric proportions of each of a plurality of prefabricated rectangular boxes based on the size of the sediment storage dam; and determining the space-filling position of each box in the sediment storage dam based on a façade, excavating foundations of the sediment storage dam based on a predetermined excavation line for the foundations; treating the base of the foundations with reinforced concrete, or concrete and cement-laid stone masonry, to produce a dam body foundation; and simultaneously preparing the boxes at sites away from the sediment storage dam, hoisting the boxes layer upon layer from the bottom to the top, starting at the dam body foundation; implementing vertical and horizontal connections between the boxes; after the boxes have been hoisted layer upon layer, filling the boxes with soil excavated during the excavation of the foundations; tamping and intensely vibrating the soil to form a dam body, filling dam abutment foundations of the sediment storage dam with cement-laid stone masonry or concrete; and filling the inside slope of the dam body with cement-laid stone masonry or concrete to form a predetermined dam body pattern, and sealing the top surface of a dam crest using cement-laid stone masonry or concrete to complete the rapidly assembled debris flow sediment storage dam. 